Rationale: Despite recent progress in treatment of melanoma, the metastatic form of the disease remains highly drug- resistant and frequently fatal. The reactivation of tumor-suppressive pathways constitutes an under-explored research avenue and presents a strategic opportunity to develop novel therapeutic interventions for this devastating disease. The explosion of data from genome-wide analysis technologies has produced a wealth of information on the genomic landscape of tumors, including mutation hotspots and copy-number alterations. Here I propose to utilize these data and analyze the functional relevance of candidate tumor- suppressor genes for melanoma formation. Research: The aims of this project are: 1) to assess the tumor-suppressive potential of ARID2, a gene encoding a chromatin regulator frequently mutated in human melanomas, and to analyze its mechanism of action, and 2) to identify the tumor-suppressor gene in a region of chromosome 10 frequently lost in human melanomas and to decipher its associated signaling pathway. I will use the zebrafish as a model organism to study the in vivo effect of gene knock-out on tumor initiation. The zebrafish is particularly suited for these studies because zebrafish embryos are genetically malleable, their large numbers provide statistical power to tumor-incidence curves and a reliable fish melanoma model is readily available. I have developed a technique for tissue-specific inactivation of genes in the zebrafish based on the CRISPR technology of genome-editing that I recently published in Developmental Cell. I will use it to evaluate the loss- of-function phenotype of candidate tumor-suppressor genes in zebrafish melanoma. The preliminary data I have obtained demonstrates the feasibility of this approach. Finally, I will investigate the cellular and molecular mechanisms of action of the identified tumor-suppressors. I expect that this research plan will yield crucial new insights into tumor-suppressive pathways in melanoma and result in the development of novel therapeutic approaches. Career plan: My long-term career goal is to lead a world-class laboratory in the forefront of cancer biology with a particular focus on the development of innovative therapies based on the analysis of tumor- suppressive mechanisms. I intend to use both the mouse and the zebrafish as investigation tools and preclinical models. To complement my knowledge of mouse models of cancer acquired during my PhD, I will carry out the mentored phase of this Award as a postdoctoral Research Fellow in the laboratory of Dr. Leonard Zon, a renowned zebrafish researcher who has made seminal contributions to the fields of developmental hematopoiesis and cancer biology. I have designed an ambitious research career development plan to achieve my immediate goals for the mentored period: 1) expand my advanced scientific and technical knowledge, and 2) prepare my transition to independence. Building on my strong background of studying cell signaling mechanisms, I will gain expertise in zebrafish techniques and perfect my cellular and molecular biology as well as biochemistry skills. Under the mentorship of Dr. Zon and a prestigious advisory committee, I will follow a structured training program to enhance my professional abilities to establish and run my own laboratory. The division of Hematology/Oncology at Boston Children's Hospital and the Harvard Medical School will provide me with the ideal environment to fully benefit from this Award and become a successful independent scientist.